Activation of sole attaching cement



July 22, 1941. w. 5. ROGERS 2,249,855

ACTIVATION OF SOLE ATTACHING CEMENT Filed Dec. 22, 1939 .V/NVE/VTUQMST/L 1' 92,

Patented July 22, 1941 2,249,855 v 2.249.855 ACTIVATION or sou:s'r'rscnmc. CEMENT Walter S. Rogers, Falmouth, Mass., assignor to UnitedShoe Machinery Corporation, Borough gf-Flemington, N. J., a corporationof New ersey Application December 22, 1939, Serial No. 310,601

3 Claims.

This invention relates to the activation, by means of an electrostaticfield, of an adhesive employed for attaching an outsole to a shoe.

It being well understood that heat may be because of the trouble andbecause of the expense involved.

Accordingly, an object of the invention is to provide an improved methodby which an elecproduced even in dielectric materials when they 5trostatic field may be' economically and quickly are inserted in a highfrequency electrostatic used for the activation of sole-attachingcement. field, it has been suggested that this manner of .In theattainment of this object and in accordproducing heat may be employedfor the activaance with an important feature of the invention, tion of asole-attaching cement of the thermomy method is carried out with theassistance of plastic type. Such cements may be of various a compositeinsole which is embodied in the forms, including thermoplastic cementsof the S e and wh is of Suc a haracter that it vinyl resin type, andusually are applied both may constitute one of the electrodes for the tth ma i f th u cle n th attaching electrostatic field. This insole inits illustrated face thereof and to the overlasted margin of formcomprises a a e of n s t metal int h upper, and anowed t dry n become'15 serted between layers of leather or leather substihard and nn-ta,ckyIt is characteristic f cgtute and adapted to serve as one of theelectrodes. ments of this type that they may be activated by In carrymgout the method, composite the application of heat and that they do notsole is one Side of an oscillator to require the use of a solvent whichcould not be aid in settmg up an electrlstatic field for Y driven off atonce after the soles have been ing sole-attachment cement, thereby tosecure a applied to the shoes but which would need-a sole to thesubstantial period of timefor their dispersion. inventmn Wm beunderstood by considers" With the thermoplastic cements, on the otherfollowing description taken in hand, hardening of the cements andpermanent g g r gggfig agg gi gggg gag g attachment of the soles followvery quickly after including a metallic sheet. part of the upper eremoval of the applied heat. layer being broken away to exp se thesheet, If an electrostatic field is to be employed for F1 g. 2 is atransverse section through this inactivating the cement, it will usuallybe found .sole on the line II-I[ of Fig. 1, and preferable to apply itto the one or more layers Fig 3 is a side elevation partly in section ofcement after the sole and th shoe have been through a shoe embodyingsuch an insole and brought into contact in the desiredposition ofpositioned on a sole resting on the pad of a attachment, and even aftera substantial pressole attaching machine. sure has been aPphed them mcontact As herein illustrated, an insole lll adapted to be an the vanouspomom? of the Sole The embodied in a shoe S comprises a metallic. plateproblem then arises of providing suitable elecpositioned between anupper layer and a trodes between wmch an electrostatfllc field lowerlayer It of insole material. Such a plate be set up to apply the heatwhere 1t is desired, may be of very thin metal, and even of the classecommicany and q this purpose of metal known as foil. It is here shown.as there has been suggested the employment of 40 having a heel portionI which Wm be used Plates, One of which is mounted the Pad principallyfor connecting the same to one side the sole-attaching Press as therebyhe of an oscillator (not shown). This portion rear-- beneath a soleresting on that pad and the other wardly of the heel breast line willnot be needed of which is attached'to or embodied inthe last for theactivation elf-cement because, in accordp n which the Shoe is made-While this is ance with ordinary practice, the sol will not betheoretically a very desirable arrangement in tt by cement t points to trear of the that it positions the held so that it can pass h l br a tline, Forwardly f th h l b a t directly through the cement as desired,it neces- ]m th plate is hown a comprising 9, .sitates either therebuilding of the la mginal band 20 which extends around the-whole monlyemployed in a shoe factory or the subof the Iorepart of the insole. Itcould equally stitution of new lasts in which electrode plates well be asolid. plate (not shown) so far as are embodied. This change, involvingas it efiectiveness is concerned. The space within would many thousandsof lasts in each factory this marginal band 20 is shown as containingawhere the method is to be employed, renders the filler 22 to avoid anyvariation in thickness bemethod unattractive to shoe manufacturers,-b0thtween the diflerent portions of the insole.

whether this will be necessary in practice depends upon the thickness ofthe metal plate II. A lead I9 attached to the plate I! may be employed,which will be broken off after the last has been removed from the shoe.Alternatively, the last thimble 3|! may be provided with, a point 32which will puncture the upper layer 14 of the insole-and make anelectric contact with the heel portion ll of the insole plate. It thenbecomes possible to attach a lead 35 to a spindle 34 by means or whichthe shoe is positioned abov the sole-attaching pad 36. This pad is showndiagrammatically as embodying a rigid box a in which there is aresilient pad member 40 having embedded in it another electrode plate"shaped approximately like the outline of a sole 50 which is to beattached to the shoe. This electrode 42 is provided with a lead 44 forattachment to one side of a high frequency oscillator (not shown) bymeans of which an electrostatic field is set up.

In using the apparatus, a sole 50 may be first positioned upon the pad36 after which the shoe 8, embodying-the insole II and mounted on itslast L, is rested upon the sole. It will be understood that inaccordance with the usual practice both the sole margin and the marginof the overlasted upper of the shoe will have been provided with acoating of suitable thermoplastic cement which has been allowed toharden. Variations in this procedure are recognized, inasmuch as it maynot always be found necessary to provide two coatings of cement andsince it may not always be desired to allow the cement to harden fullybefore the shoe and sole are brought together. Contact is made (as shownin Fig. 3) with the electrode l2 through the thimble 30 and the spindle34, this spindle also serving as an abutment, along with anotherabutment 46, to enable the shoe and sole to be brought into firm contactby means of relative movement between the pad 36 andthe members 34 and46. Upon the closing of the circuit leading to the oscillator, a highfrequency field will be set up which will activate 'the cement layerslying between the electrode plate I! and the electrode plate 42. Thisapplication of current will be for a very short period of time, such asa few seconds, and upon the disconnection of the oscillator the workwill coolvery promptly, allowing the cement to harden and attach thesole to the. shoe.

Having described my invention, what I claim as new and desire to secureby Letters Patent of the United States is:

1. That improvement in methods of attaching soles to shoes whichcomprises activating thermoplastic cement positioned between the outsoleand shoe bottom by a high frequency electrostatic field produced betweena condenser plate forming a permanent part of the insole of the shoe anda plate located externally of the shoe.

2. That improvement in methods of cementattaching soles to shoes whichcomprises heating sole-attaching cement, located between the outsole andthe shoe bottom, while the shoe and outsole are under pressure, by meansof a high frequency electrostatic field produced between condenserelectrodes one of which forms a permanent part of the shoe bottom, whilethe other is located externally of the shoe.

3. A method of making shoes which consists in lasting an upper over aninsole which has a layer of sheet metal in its forepart, providing anelectrical connection to said sheet metal extending outside of thelasted shoe, applying cement to the overlasted margin of the upper,presenting to said shoe a previously cemented sole, positioning saidshoe and sole in an electrostatic field provided between the insoleelectrode and another electrode outside of the shoe, thereby to activatethe cement to attach the sole to the shoe, and applying pressure toforce the sole into firm contact with the shoe.

WALTER S. ROGERS.

